As offshore drilling and completion operations progress into deeper waters, especially in depths of water greater than 1000 feet, many relatively simple surface operations become complex and costly. One frequent operational requirement is that of engaging a stab connector with a receptacle connector for the purpose of applying hydraulic flow and pressure to operate or drive a function.
In many situations, interventions are required to maintain the performance of an oil or gas well. Interventions typically include removing debris from a well, shifting production levels in a well, unloading fluid from a well, stimulation of a production zone, well logging, as well as other well operations. Often, interventions require injection of one or more fluids into a well, for example, water, nitrogen, hydrate inhibitors, acids, and cements. Such fluids may be transported to the well site, stored in transportable containers, and then pumped into well with specialized pumping equipment.
Subsea well interventions can be more complicated due to inaccessibility of the well. A typical subsea well intervention includes utilization of a mobile offshore drilling unit and related specialized equipment. Subsea stab connector assemblies (or “hot stab”) are commonly used to connect underwater piping or equipment. Stab assemblies are generally configured as two-component assemblies that include a female “receptacle” and a male insert called a “stab.” The female receptacle is typically attached to subsea equipment or a subsea structure. The corresponding stab is often connected to hoses or hydraulic lines, running to surface equipment or facilities. The stab is typically configured for manipulation by a remote operated sub-sea vehicle (ROV) or manually by a diver. During use, the ROV or diver inserts the stab into the receptacle to connect the sub-sea equipment to the surface equipment or facilities.
These types of operations have seen a history of field problems in that the force of insertion is somewhat unpredictable depending on a number of factors, such as percent squeeze of the seals, surface finishes, shape of entrance chamfers, hardness of the seal members, cross sectional area of the seal members, and the outer diameter of the seal members.
Therefore, there is a need for a stab connector that can be quickly and easily engaged and disengaged from a receptacle connector.
Performing maintenance on subsea connectors is difficult and expensive. A need therefore exists for a stab connector assembly having a simple and reliable design that is not susceptible to contamination, is easy to maintain, and provides the ability to reliably and securely form a connection.
A need also exists for well equipment connectors that can communicate fluids at high pressures and withstand strong linear and bending forces exerted on the stab connector.